Foiled paper and method of producing same.



' APPLICATION FILED 1111111111 6.

Patented May 11, 1909.

UNITED sTA EsrnTENT OFFICE.

GEORGE runnnmcn MANSBRIDGE, or SANDERSTEAD, ENGLAND.

FOILED PAPER AND METHOD OF PRODUCING Specification of Letters Patent.

Patented May 11, 1909.

Application filed January 13, 1906. Serial No. 295,993.

paper, foiled parchment and the like and it.

has for its ob ect to improve the quality of such material so as to render the same more suitable for electrical purposes. By foiled paper or foiled-parchment I do not mean paper or parchment to which solid metal foil has been attached or applied but paper, parchment and the like coated with a thin film of metal which has been-applied to the paper in the form of a powder or paste, and is integral with the paper, in the well known way. For the purposes of this invention the thin metallic film must be electrically continuous and conducting and must be firmly adherent to the paper. I improve the quality of the material by treating it,.

prior to use, in such a manner as more efliciently to insulate, in the case of material foiled, or coated, on both sides, the two conductin coatin s from each other, and in the case of mater1al foiled, or coated, on one side only, the foiled surface from the plain surface.

For convenience of description reference will hereinafter be niade sim ly to foiled paper as describing the varlous materials to which this invention is applicable.

In the use of foiled paper for electrical purposes it is often desirable that the foiled surface shall be electrically conducting and continuous with respect only to that side of the paper on which it is situate, 2'. 6., in the case of paper foiled on one side only, that a sheet of metalas tinfoilplaced in contact with the 'plain side shall be completely insulated, by the dielectric (the body paper), from the foiled side of the paper; similarly,

in the case of paper foiled on both sides, that the two conducting surfaces shall becompletely insulated from each other b the body paper. tain, particularly with thin paper,- since dcfective places in the dielectric, caused by weak spots or pinholes in the body paper, or by grains of metal being partially or completely driven through the paper in the process of manufacture, cannot be altogether This desideratum is di cult to ob avoided. Consequently, whensuch paper is used for electrical purposes, 6. g., as a condenser, inductive resistance or the like, there is a tendency for the defective places to break down or to cause a short circuit when the dielectric is subjected to electrical pressure.

By means of my invention I produce an improved quality of foiled paper in which the defective places are relieved of part or all of the electrical strain which would otherwise come, upon them when the dielectric was Ill subjected to electrical pressure. By thus relieving the defective places from strain 1, in eifect, eliminate them altogether and 1 thus produce a paper from which more uniform and more satisfactory results can be obtained when the same is used for electrical purposes, c. as a condenser, inductive resistance or the like. '1' attain this result by subjecting the foiled paper to a process which results in the conducting coating over the small area around and immediately adjacent to the defective places being removed or rendered non-conducting or practically non-conducting. This process consists in passing the foiled paper from end to end around, under. over or between conducting rollers, brushes or the like, one roller (or rollers) making contact with one side of the foiled paper, and

being connected to one pole' of a battery or its equivalent, and the other roller (rollers) making contact with the other side of the foiled paper, and being connected to the other pole of the battery, the two rollers or two sets of rollers) being otherwise insulated from each other. Consequently when a defective place touches a roller which is in 0011-.

tact with the plain side of the paper, a current passes through the defective place either by direct conduction, if there is an existing pinhole, or by a disruptive discharge if the defective place is not strong enough to prevent puncture. This current is necessarily restricted at the point where it passes from one side of the paper to the other to a very small area, and in consequence the current density in that part of-the metallic coating which is immediately adjacent to the defective place is great and a spark is momentarily produced. This burns away ,or' otherwise. renders non-conducting the metallic coating in the immediate neighborhood of the defective place but without burning awaythe body paper exceptto a very minuteextent. Consequently the puncture is electrically isolated ing out the treatment of the foiled paperf such device as that shown in the lower part' per coated on both sides, the defective places may be similarly burned out, but as the foiled surfaces are continuous on both sides there is not the same necessity to use conducting brushes or rollers, although, for purposes of manipulation. it is convenient to use such brushes or rollers. 4

The mechanical deviceadopted for carrymay be of any simple kind, such as illustrated in the accompanying drawing which represents a convenient mechanical device for treating, paper foiled on one side. In the said drawing which shows all that is material for the purpose of this description, Figure 1 is substantially a side elevation of the mechanical device showing also the foiled paper and a diagrammatic View of the electrical connections, Fig. 2 bein a plan of said mechanical device and foiled Referring to the drawing, a a represent the insulated rollers, brushes or the like connected to one pole of-the battery 6, the insulated roller 6 being connected to the other pole and making contact with the foiled side of the paper;d (Z- are the rolls of foiled paper, e is a capacity used to increase the current at the moment of short-circuiting, and f is a resistance used to prevent the condenser discharge taking place with too great suddenness.

Should 't be necessary to detect and call attention to any want of continuity in the foiled surface, due to defective joints or other causes, it is convenient to use some of Fig. 1,which comprises a low resistance relay g, a bell h, a conducting brush or roller j, and the necessary battery and connecting Wire's. As ,will beunderstood, the electrical circuit will be complete so long as there is continuity of the foiled surface between the rollervo and the brush 7'.

. this continuity be broken, the armature of the relay y will be drawn back, thus com- Should pleting anotherlocal circuit and ringing the bell h. I'do not however restrict myself to the precise arrangement of the breaking down apparatus shown by the 1 drawing, 6. only two rollers may be cmi ployed, one connected to each pole of the battery, but I prefer to use two rollers in contact with the plain side of the paper in order to provide additional security. .Obviously, three or more such rollers may be used if desired. Further, the condenser e and the resistance may be dispensed with, but it is then necessary to use a higher voltage between the rollers to produce an equivalent result.

The value of the voltage (and of the capacity and resistance whensuch are used) required to give the best results in any particular case can readily be determined by experiment, due regard being had to the conditions under which the finished product is to be used. In choosing or adjusting the values of the voltage, capacity and resistance, regard should be had to the fact that the best result may be expected when the puncture produced is small and clean and when the conducting material is well cleared away from. the immediate neighborhood of the puncture.

Claims.

1. The hereindescribed method of treatof powdered metal so as to avoid the detrimental efi'ects of defective places therein when'used for electric purposes which consists in subjecting each sheet separately to electric currents whereby the metal in proximity to any defective places in the sheet is fused and the defective places isolated, substantially as described.

2. As an article of manufacture, a sheet of paper coated with a thin film of powdered metal for electrical purposes having the defective places in the paper isolated from the metal or foil, substantially as described. GEORGE FREDERICK MANSBRIDGE.

Witnesses H. D. JAMEsoN,

F. L. RAND. 

